hi tuck,
I am not being difficult, but to fully answer your question would take pages!
An ideal opa:
Infinite input impedance
Zero output impedance.
Zero voltage offset
Zero drift
Infinite bandwidth
Able to swing the Vout from rail to rail voltage.
........etc
The practical opa cannot meet all these requirements, in one way or another.
Thanks for all the information. I do found those defination at wikipedia, but i juz don't know how to explain "how and why pratical amplifier deviate from the idealized model".
Keep in mind that opamps are physical electronics systems. Physical systems never have infinite anything, and they are susceptible to any kind of error exposed that you can think of.
Thanks for all the information. I do found those defination at wikipedia, but i juz don't know how to explain "how and why pratical amplifier deviate from the idealized model".
Think of it as simply perfect theory Vs practical reality. For instance noise is not a component in a perfect op-amp but in reality they all generate a certain amount of internal noise. If low noise is a requirement then one would select from the many op amps available for the one with the lowest noise specifications that meets the circuit requirements. This same selection process would apply to all the various specifications and is part of any initial design, matching circuit parameter requirements to device specifications.
hi tuck,
I am not being difficult, but to fully answer your question would take pages!
An ideal opa:
Infinite input impedance
Zero output impedance.
Zero voltage offset
Zero drift
Infinite bandwidth
Able to swing the Vout from rail to rail voltage.
........etc
The practical opa cannot meet all these requirements, in one way or another.